The Contrary Laws of Reflection

[IATF]

So, I was just working out on color and reflection but then turned a little bit confused. The main phenomenon we study everywhere is that a colored object absorbs light of all wavelengths excepting the light of its own color. Then comes the problem. As per that, if I beam a GREEN LASER on a RED object, it must have absorbed all the light. But this is not what happens, the Green light of laser is reflected in all of the directions and can be seen from many positions.

 

[Drakkith]

No object is a perfect absorber of any wavelength, let alone a broad range. A black piece of paper merely absorbs a much larger percentage of the incoming light than a white piece of paper. The same is true of all other objects. A red apple reflects more light in the red end of the spectrum than the rest, but it does not absorb all of the non-red light falling on it.

 

[IATF]

Is the percentage of light absorbed proportional to the amount of light falling on it, or the value is predetermined for the object?

 

[sophiecentaur]

Is the percentage of light absorbed proportional to the amount of light falling on it, or the value is predetermined for the object?

What is your opinion about that?
Human colour vision is very clever and also very limited at the same time so you cannot rely on what you 'see' to answer your question.

 

[IATF]

I asked this question because we know that anything seems brighter and more detailed in more light, and concluded that that light reflected out could be proportional to light absorbed. What's your opinion towards this?

 

[sophiecentaur]

I have no reason to think that the proportion of light reflected from a surface would change according to the amount of light (with the same spectrum) falling on it. That simple relationship could well change if the level of light energy were high enough to alter the surface (e.g. change its temperature to red hot). What your eyes / brain make of a scene is not related in any simple way to the actual situation; the retina is not a simple linear detector, for instance and visual acuity depends upon incident light levels.
My "opinion" is based on standard teaching and personal measurements. Have you read the standard stuff about reflectivity of light? It's always a good idea to start with some reading before asking questions.

 

[ZapperZ]

I asked this question because we know that anything seems brighter and more detailed in more light, and concluded that that light reflected out could be proportional to light absorbed. What's your opinion towards this?

This is not necessarily true, because you are forgetting one thing: the sensitivity of the eye for a particular wavelength.

I wrote about the shortcoming of the human eye as a detector already. It is possible that an incoming light may be in the range that the eye is less sensitive to, while the reflected light is in the range that the eye is more sensitive to. This then will make it appear that the reflected light is brighter than the incident light. While not strictly in the same physics, blacklight reflection is one such example.

The ONLY way to do this objectively (i.e. not to include the shortcoming of our eye into the equation) is to look at UV-VIS-type experiments. Otherwise, you will always be questioned on whether your eye is deceiving you with what you think you saw.

Zz.

 

[my2cts]

@OP
What laws of reflection are you talking about and how are they "contrary" ?